Lindqvist, 41, is currently in the process of divorcing her husband, a plastic surgeon. She and Wilson -- who reportedly met several years ago when he hired her to be his trainer -- are not together, the source says, but he's made it clear that he'll be there for her and, when the time comes, the baby.

"Owen is very involved with the pregnancy," the source explains. "He isn't in a relationship with Caroline, nor do they plan to be in one, but he is very supportive of everything. They see each other and talk often about what they want for the child. Owen is very open-minded about everything and has told Caroline he will do whatever he can."

This will be Wilson's second child. The Wedding Crashers star is already dad to son Robert Ford, 2, with ex-girlfriend Jade Duell. Shortly after the little boy's birth on Jan. 14, 2011, the actor said fatherhood was "very exciting."

"I'm glowing," he quipped in an interview with Jay Leno, noting that his son was "very cute" and "doing well."

"What they say about newborns and not getting a lot of sleep -- that's true," he added. "You look at every place as a potential nap place. I'm looking at this couch -- maybe at commercial break [I'll take a] little shut-eye there."